private static void loadDirectly(string filePath, List <MidiTrack> midiTracks, ref ushort timeDivision) // returns the MIDI loaded in the List of all individual tracks
{
// FileStreams seem to have their own buffering layer so there is no need for an additional Buffered Stream
FileStream midiFileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
BinaryReader midiBinaryStream = new BinaryReader(midiFileStream);
midiFileStream.Position = 0xA; // seek to the amount of tracks in the MIDI file
int numTracks = midiBinaryStream.ReadByte() << 8 | midiBinaryStream.ReadByte();
timeDivision = (ushort)(midiBinaryStream.ReadByte() << 8 | midiBinaryStream.ReadByte());
// finished reading the header data, now continue transscribing the tracks
for (int currentTrack = 0; currentTrack < numTracks; currentTrack++)
{
MidiTrack cTrk = new MidiTrack();
midiTracks.Add(cTrk); // we have to create the object of the track first and we can add it later to out track list if the track was transscribed into it's objects
long currentTick = 0;
NormalType lastEventType = NormalType.NoteOFF;
byte lastMidiChannel = 0;
// check if the track doesn't begin like expected with an MTrk string
byte[] textString = new byte[4];
midiBinaryStream.Read(textString, 0, 4);
if (Encoding.ASCII.GetString(textString, 0, 4) != "MTrk")
{
throw new Exception("Track doesn't start with MTrk string!");
}
byte[] intArray = new byte[4];
midiBinaryStream.Read(intArray, 0, 4); // read the track length
// this value isn't even needed, so we don't do further processing with it; I left it in the code for some usage in the future; no specific plan???
// now do the event loop and load all the events
#region EventLoop
while (true)
{
// first thing that is done is getting the next delta length value and add the value to the current position to calculate the absolute position of the event
currentTick += readVariableLengthValue(midiBinaryStream);
// now check what event type is used and disassemble it
byte eventTypeByte = midiBinaryStream.ReadByte();
// do a jumptable for each event type
if (eventTypeByte == 0xFF) // if META Event
{
byte metaType = (byte)midiFileStream.ReadByte();
long metaLength = readVariableLengthValue(midiBinaryStream);
byte[] metaData = new byte[metaLength];
midiBinaryStream.Read(metaData, 0, (int)metaLength);
if (metaType == 0x2F)
{
break; // if end of track is reached, break out of the loop, End of Track Events aren't written into the objects
}
cTrk.midiEvents.Add(new MetaMidiEvent(currentTick, metaType, metaData));
}
else if (eventTypeByte == 0xF0 || eventTypeByte == 0xF7) // if SysEx Event
{
long sysexLength = readVariableLengthValue(midiBinaryStream);
byte[] sysexData = new byte[sysexLength];
midiBinaryStream.Read(sysexData, 0, (int)sysexLength);
cTrk.midiEvents.Add(new SysExMidiEvent(currentTick, eventTypeByte, sysexData));
}
else if (eventTypeByte >> 4 == 0x8) // if Note OFF command
{
byte par1 = midiBinaryStream.ReadByte();
byte par2 = midiBinaryStream.ReadByte();
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, (byte)(eventTypeByte & 0xF), NormalType.NoteOFF, par1, par2));
// save the last event type and channel
lastEventType = NormalType.NoteOFF;
lastMidiChannel = (byte)(eventTypeByte & 0xF);
}
else if (eventTypeByte >> 4 == 0x9) // if Note ON command
{
byte par1 = midiBinaryStream.ReadByte();
byte par2 = midiBinaryStream.ReadByte();
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, (byte)(eventTypeByte & 0xF), NormalType.NoteON, par1, par2));
// save the last event type and channel
lastEventType = NormalType.NoteON;
lastMidiChannel = (byte)(eventTypeByte & 0xF);
}
else if (eventTypeByte >> 4 == 0xA) // if Aftertouch command
{
byte par1 = midiBinaryStream.ReadByte();
byte par2 = midiBinaryStream.ReadByte();
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, (byte)(eventTypeByte & 0xF), NormalType.NoteAftertouch, par1, par2));
// save the last event type and channel
lastEventType = NormalType.NoteAftertouch;
lastMidiChannel = (byte)(eventTypeByte & 0xF);
}
else if (eventTypeByte >> 4 == 0xB) // if MIDI controller command
{
byte par1 = midiBinaryStream.ReadByte();
byte par2 = midiBinaryStream.ReadByte();
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, (byte)(eventTypeByte & 0xF), NormalType.Controller, par1, par2));
// save the last event type and channel
lastEventType = NormalType.Controller;
lastMidiChannel = (byte)(eventTypeByte & 0xF);
}
else if (eventTypeByte >> 4 == 0xC) // if Preset command
{
byte par1 = midiBinaryStream.ReadByte();
byte par2 = 0x0; // unused
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, (byte)(eventTypeByte & 0xF), NormalType.Program, par1, par2));
// save the last event type and channel
lastEventType = NormalType.Program;
lastMidiChannel = (byte)(eventTypeByte & 0xF);
}
else if (eventTypeByte >> 4 == 0xD) // if Channel Aftertouch command
{
byte par1 = midiBinaryStream.ReadByte();
byte par2 = 0x0; // unused
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, (byte)(eventTypeByte & 0xF), NormalType.ChannelAftertouch, par1, par2));
// save the last event type and channel
lastEventType = NormalType.ChannelAftertouch;
lastMidiChannel = (byte)(eventTypeByte & 0xF);
}
else if (eventTypeByte >> 4 == 0xE) // if Pitch Bend command
{
byte par1 = midiBinaryStream.ReadByte();
byte par2 = midiBinaryStream.ReadByte();
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, (byte)(eventTypeByte & 0xF), NormalType.PitchBend, par1, par2));
// save the last event type and channel
lastEventType = NormalType.PitchBend;
lastMidiChannel = (byte)(eventTypeByte & 0xF);
}
else if (eventTypeByte >> 4 < 0x8)
{
byte par1 = eventTypeByte;
byte par2;
switch (lastEventType)
{
case NormalType.NoteOFF:
par2 = midiBinaryStream.ReadByte();
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, lastMidiChannel, NormalType.NoteOFF, par1, par2));
break;
case NormalType.NoteON:
par2 = midiBinaryStream.ReadByte();
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, lastMidiChannel, NormalType.NoteON, par1, par2));
break;
case NormalType.NoteAftertouch:
par2 = midiBinaryStream.ReadByte();
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, lastMidiChannel, NormalType.NoteAftertouch, par1, par2));
break;
case NormalType.Controller:
par2 = midiBinaryStream.ReadByte();
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, lastMidiChannel, NormalType.Controller, par1, par2));
break;
case NormalType.Program:
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, lastMidiChannel, NormalType.Program, par1, 0x0));
break;
case NormalType.ChannelAftertouch:
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, lastMidiChannel, NormalType.ChannelAftertouch, par1, 0x0));
break;
case NormalType.PitchBend:
par2 = midiBinaryStream.ReadByte();
cTrk.midiEvents.Add(new MessageMidiEvent(currentTick, lastMidiChannel, NormalType.PitchBend, par1, par2));
break;
}
}
else
{
throw new Exception("Bad MIDI event at 0x" + midiBinaryStream.BaseStream.Position.ToString("X8") + ": 0x" + eventTypeByte.ToString("X2"));
}
} // end of the event transscribing loop
#endregion
} // end of the track loop
midiBinaryStream.BaseStream.Close();
} // end of function loadDirectly
public static void saveToFile(string filePath, List <MidiTrack> midiTracks, ushort timeDivision)
{
Console.WriteLine("Saving MIDI to type 1 file...");
// first of all check if a file with the name already exists
if (File.Exists(filePath))
{
File.Delete(filePath);
}
FileStream midiFileStream = new FileStream(filePath, FileMode.Append, FileAccess.Write, FileShare.None);
BinaryWriter midiWriter = new BinaryWriter(midiFileStream);
Console.WriteLine("The new MIDI file has {0} tracks!", midiTracks.Count);
// first of all write MIDI header string
midiWriter.Write(Encoding.ASCII.GetBytes("MThd"));
// writer the header chunk length (=6)
midiWriter.Write(intToBigEndian(6));
// write the midi file type (=1)
midiWriter.Write(ushortToBigEndian(1));
// write the amount of tracks
midiWriter.Write(ushortToBigEndian((ushort)midiTracks.Count));
// write the time division
midiWriter.Write(ushortToBigEndian(timeDivision));
// finished writing the header, now do the tracks
long[] trackHeaderOffset = new long[midiTracks.Count];
long[] trackStartOffset = new long[midiTracks.Count];
long[] trackEndOffset = new long[midiTracks.Count];
for (int currentTrack = 0; currentTrack < midiTracks.Count; currentTrack++)
{
MidiTrack cTrk = midiTracks[currentTrack];
trackHeaderOffset[currentTrack] = midiWriter.BaseStream.Position; // save the offset to the track header
// write the header info
midiWriter.Write(Encoding.ASCII.GetBytes("MTrk"));
midiWriter.Write((int)0); // write 0 into the chunk length slot; it'll get filled later; 0 is the same in Little Endian as in Big, so we can use the normal int32 writing
trackStartOffset[currentTrack] = midiWriter.BaseStream.Position; // save the track beginning (doesn't point to the header, it points to the data)
long currentTick = 0; // init the current tick to 0 to calculate Delta Time values
for (int currentEvent = 0; currentEvent < cTrk.midiEvents.Count; currentEvent++)
{
// write the Delta time to the stream
midiWriter.Write(VariableLength.ConvertToVariableLength(cTrk.midiEvents[currentEvent].absoluteTicks - currentTick));
// write the actual Event data
midiWriter.Write(cTrk.midiEvents[currentEvent].getEventData());
currentTick = cTrk.midiEvents[currentEvent].absoluteTicks;
}
midiWriter.Write((byte)0x0); // write delta time for track end
midiWriter.Write((byte)0xFF); // write META event byte
midiWriter.Write((byte)0x2F); // write End of Track byte
midiWriter.Write((byte)0x0); // the length of this META event data is 0 (no data follows)
trackEndOffset[currentTrack] = midiWriter.BaseStream.Position; // calc the length of the event data and backup the position
} // end of track loop
midiWriter.BaseStream.Close();
// close the filestreams and create a new one to edit the file
midiFileStream = new FileStream(filePath, FileMode.Open, FileAccess.Write, FileShare.None);
midiWriter = new BinaryWriter(midiFileStream);
for (int currentTrack = 0; currentTrack < midiTracks.Count; currentTrack++)
{
midiWriter.BaseStream.Position = trackHeaderOffset[currentTrack] + 4;
midiWriter.Write(intToBigEndian((int)(trackEndOffset[currentTrack] - trackStartOffset[currentTrack])));
}
midiWriter.Close();
// close filestream and finish
Console.WriteLine("Successfully finished creating MIDI file!");
} // end of function
